The present invention concerns a prime mover assembly operated by a liquid stream for reciprocatingly carrying a device along a rectilinear axis. The invention further relates to a body washing and massaging apparatus incorporating the inventive prime mover assembly.
There is often, in a wide variety of applications, a need to provide a particular device with reciprocal movability along a rectilinear axis. At times, there is a further requirement that the apparatus intended to enable such movement be usable in an environment in which the presence of fumes or fluids or certain conditions necessitate against powering of the apparatus with electricity or other commonly-utilized power sources. One such example of this situation occurs where the environment is extremely wet or damp such that the presence of electrical current presents a real risk and possibility of hazardous shock--as in a bathroom or, more particularly, in a shower stall or bathtub.
A more specific example involves the washing of one's own body, whereby great difficulty is almost always encountered in effectively cleansing the back due to the relatively short reach and extreme angular dexterity required of the arms. The same problem is well known among those suffering chronic or periodic back problems which can be alleviated by appropriate massaging manipulation of the concerned area, and massaging of the back even without a direct medical need therefor is almost universally recognized as providing mental benefits through physical loosening of tense back muscles. Of course, either of these situations can be satisfactorily attended to by another person, although the other's presence or willingness to assist whensoever necessary cannot always be depended upon.
Various devices have been proposed for use in a shower environment and to provide capabilities of this sort. U.S. Pat. No. 3,768,462 discloses a scrubbing and massaging apparatus for the human body including a scrubbing head movable along a vertical path. The scrubbing head is carried on a pair of cables driven by a pulley-type hydraulically-driven arrangement in which a liquid, such as water, alternately fills the top and bottom of a hollow cylinder to correspondingly move a piston contained therein. As the scrubbing head reaches the respective top and bottom of its desired path of travel, it engages limit stops secured on a rod for moving the rod and causing a reversal in the direction of head travel.
The apparatus of this prior art patent includes a number of distinct operating disadvantages, not the least of which is inherent in its use of cables and pulleys which are undesireably subject to stretching, breakage and slippage in the notably wet environment of a bathroom shower. As a consequence, the water pressure necessary to effectively operate the apparatus is undesireably great and its use can involve significant wasting of water supplies that are often inadequate to allow for such waste.
It is accordingly the desideratum of the present invention to provide a prime mover assembly capable of reciprocating a device along a rectilinear axis utilizing a relatively low pressure source of liquid for providing its operating power.
It is another object of the invention to provide apparatus for scrubbing and massaging a human body--and more particularly the back thereof--incorporating the inventive prime mover assembly.
It is further object of the invention to provide such a scrubbing and massaging device that is inherently reliable, utilizes component parts that are appropriate for use in a bathroom shower environment, and that is capable of providing long and substantially maintenance free operation for an extended period of time.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.